Method and system for adjusting a position of an object

ABSTRACT

According to one embodiment of the present invention, a method for adjusting a position of an object to compensate for tilt includes providing a rotatable base supporting an object and directing the object relative to the base such that the position of the object is controlled relative to a first axis. The object is stabilized along a second axis. The object is positioned relative to the base using at least one bearing arm. The at least one bearing arm movably couples the object to the base at a first position relative to a third axis and a fourth axis. The at least one bearing arm includes a first portion and a second portion, which are coincident with the third axis and fourth axis, respectively. The object is adjusted to a second position using the at least one bearing arms to maintain the first axis when a tilt angle of the base is detected.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/775,327filed Jul. 10, 2007 entitled “Method and System for Adjusting a Positionof an Object,” now U.S. Pat. No. 7,896,607, which is a continuation inpart of U.S. application Ser. No. 11/555,901, filed Nov. 2, 2006entitled “Method and System for Adjusting a Position of an Object,” nowU.S. Pat. No. 7,241,103, which is a divisional of U.S. application Ser.No. 10/951,044, filed Sep. 24, 2004 entitled “Method and System forAdjusting a Position of an Object,” now U.S. Pat. No. 7,223,063.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the field of mechanics and morespecifically to a method and system for adjusting a position of anobject to compensate for tilt.

BACKGROUND OF THE INVENTION

In combat or other information gathering situations, a sensor package orother object mounted on a vehicle or vessel in motion may be used toobtain location or other information about the environment or anidentified target. Alternatively, the object may be used to sight on thetarget for long-range firing or other purposes. Accordingly, the sensorpackage or other object may establish a line of sight with theidentified target, which may be located some distance from the sensorpackage or other object, or another generally horizontal field.

While the information is being obtained or weaponry is being engaged,the line of sight directed at the identified target must be maintained.Such sensor packages and objects, however, are typically supported on amoving vehicle, aircraft, or other vessel. As the supporting machinerymoves along the uneven surface of the ground, air, or sea, changes inpitch, roll, or elevation may cause the line of sight with theidentified target or other horizontal field to be broken if theresulting change in the position of the sensor or other object is notcompensated for.

Typical sensors and other objects are mounted with gimbal systems thatoperate to adjust the position of the sensor package or other objectalong two or more axes. In such gimbal systems, however, the mountingsystem of the gimbal are typically bulky structures that encircle or atleast partially encircle the sensor package or other object.Additionally, each of the two or more degrees of freedom provided by thegimbal are orthogonal to each other and operate independently of everyother axis. Because the mounting system must be adjusted to adjust theposition of the sensor package or other object, a great deal of massmust be repositioned to maintain or realign the line of sight with theidentified target. Additionally, such systems may at least partiallyobstruct the view of the sensor package or other object and/or mayimpact the usability of the sensor data.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method and system fordirecting an object are provided that substantially eliminate or reducethe disadvantages and problems associated with previously developedsystems and methods.

According to one embodiment of the present invention, a method foradjusting a position of an object to compensate for tilt includesproviding a rotatable base supporting an object and directing the objectrelative to the base such that the position of the object is controlledrelative to a first axis. The object is stabilized along a second axis.The object is positioned relative to the base using at least one bearingarm. The at least one bearing arm movably couples the object to the baseat a first position relative to a third axis and a fourth axis. The atleast one bearing arm includes a first portion and a second portion,which are coincident with the third axis and fourth axis, respectively.The object is adjusted to a second position using the at least onebearing arm to maintain the first axis when a tilt angle of the base isdetected.

Depending on the specific features implemented, particular embodimentsof the present invention may exhibit some, none, or all of the followingtechnical advantages. A technical advantage of one embodiment is thatthe position of an object may be adjusted by rotating the object about aderoll axis to reposition the object to compensate for tilt.Specifically, in certain embodiments, the object may be supported in afirst position that is skewed relative to an elevation axis. Because theangle between the elevation axis and the deroll axis is less than ninetydegrees, in particular embodiments, a technical advantage may be thatobject is mounted on a smaller structure than other mass derolls.

A further technical advantage of one embodiment may be that the objectis supported at two corresponding pivot points rather than by a collaror other encircling mounting system. In another embodiment, the objectmay be supported at a single pivot point rather than by a collar orother encircling mounting system. Another technical advantage may bethat the collarless mounting system is substantially lighter and stifferthan collared mounting systems. As a result, less mass must be moved tomaintain the line of sight of the object. Still another technicaladvantage may be that the collarless mounting system increases theunobstructed sensor surface area that may be used for obtaining sensordata.

Other technical advantages are readily apparent to one skilled in theart from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and forfurther features and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates one embodiment of a system for adjusting the positionof an object according to the present invention;

FIG. 2 illustrates one embodiment of a bearing arm that may be used inthe system of FIG. 1;

FIG. 3 illustrates a top view of one embodiment of an object with threecooperating degrees of freedom;

FIG. 4 illustrates a front view of one embodiment of an object withthree cooperating degrees of freedom in an adjusted portion;

FIG. 5 illustrates another embodiment of a system for adjusting theposition of an object according to the present invention; and

FIG. 6 is a flowchart of one embodiment of a method for adjusting theposition of an object according to the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention and its advantages are bestunderstood by referring to FIGS. 1 through 6 of the drawings, likenumerals being used for like and corresponding parts of the variousdrawings.

FIG. 1 illustrates one embodiment of a system 10 for adjusting theposition of an object 12. In the illustrated embodiment, object 12comprises a sensor package that may include, for example, anelectro-optical infrared sensor such as that was offered for sale underthe name Future Combat Systems Medium Range EO/IR Sensor (SCLIN 0001)and offered by Raytheon the assignee of this patent application. Futureapplications may include Reconnaissance, Surveillance, and TargetAcquisition (RSTA) Electro-Optical sensors. Thus, object 12 may includeappropriate circuitry for image or thermal sensory. Additionally, object12 may include circuitry appropriate for establishing a line of sightwith a target located some distance from object 12 or another generallyhorizontal field.

Although an image sensor is illustrated, it is recognized that object 12may include any object which may be directed at or sighted on a target.For example, object may include any object appropriate for gatheringinformation about an identified target. In particular embodiments,object 12 may be used in combat situations. For example, object 12 maybe used in ground-based, air-based, and sea-based combat applications.Example combat uses for object 12 as described in this document,however, are merely provided as example applications for the use ofobject 12. It is recognized that object 12 may be used in anyapplication requiring the sustained maintenance of a line of sight orother generally horizontal field with an identified target.

In various embodiments, object 12 may be coupled to or supported by anyof a variety of vehicles, machinery, or other object stationary or inmotion. For example, in a combat situation, object 12 may be coupled toan automobile, a tank, a ship, a helicopter, or an airplane. Becausesuch objects typically do not stay on a steady horizontal course, it maybecome necessary for the line of sight established by object 12 on anidentified target to be reestablished. For example, the vehicle or othermachinery supporting object 12 may become tilted as the machinerytravels along a surface or through the air. The changes in pitch or rollof the machinery may cause the line of sight of object 12 to be movedfrom the identified target or the generally horizontal field tootherwise be altered. Because object 12 has three cooperating degrees offreedom, however, object 12 may be automatically and mechanicallyrepositioned such that the line of sight, or other horizontal field, ismaintained or reestablished by object 12 and directed at the target.

As illustrated, object 12 is supported on a rotatable base 14 that maybe mounted on the turret of a vehicle or other movable machine. Inparticular embodiments, base 14 includes a base support 16 and a basecradle 18. Base cradle 18 is rigidly fixed to base support 16 andincludes two opposing arms to couple to opposing sides of object 12. Inparticular embodiments, the two opposing arms may couple to object 12 attwo opposing pivot points located on opposing sides of object 12. Aswill be described in more detail below, base support 16 is rotatablerelative to the machinery on which base 14 is mounted. Because basecradle 18 is rigidly fixed to base support 16, however, the rotation ofbase support 16 relative to the vehicle or other supporting machinerycauses the rotation of base cradle 18 and, thus, object 12, which issupported thereon. Because object 12 is coupled to base 14 at the twoopposing pivot points, object 12 is coupled to base 14 and, thus,mounted on any supporting machinery using a collarless mounting system.As a collarless mounting system, system 10 may provide a smallerstructure than other mass derolls. As a result, system 10 issubstantially lighter and stiffer than collared mounting systems, andless mass must be moved to maintain first axis 20 when base 14encounters tilt. Additionally, the unobstructed sensor surface area thatmay be used for obtaining sensor data may be substantially increased.

System 10 includes a director or controller, not illustrated, thatoperates to control the position of object 12 and the movement of allaxes. For example, the director may control the rotation of object 12about first axis 20 defined by object 12. As illustrated, first axis 20extends outward from object 12 in a direction that is substantiallyperpendicular to the page. In particular embodiments, first axis 20 mayinclude a line of sight or other generally horizontal field defined byor established by or established by object 12. The position of object 12may be controlled relative to this line of sight or horizontal field.

Base 14 also operates to control the position of object 12 about asecond axis 22. Object 12 may be stabilized with respect to second axis22. In particular embodiments, second axis 22 is an azimuth axis whichdefines 360 degrees of rotation. Base cradle 18 couples to base support16 to establish second axis 22 rotation with respect to the vehicle.Base cradle 18 may be rotated about second axis 22 to enable object 12to also rotate 360 degrees about second axis 22. Thus, where object 12comprises a sensor package mounted on the turret of a combat vehicle,the sensor package may be rotated 360 degrees relative to azimuth axis22. As a result, first axis 20, or the line of sight defined by object12, may be directed at and aligned with any target on any side of thecombat vehicle. The rotation of object 12 about second axis 22represents a first degree of freedom.

Two bearing arms 24 movably couple object 12 to base 14 in a manner thatresults in object 12 being movable with respect to at least twoadditional cooperating degrees of freedom. Two bearing arms 24 coupleobject 12 to base 14 at two respective and opposing pivot points oneither side of object 12. Thus, bearing arms 24 cooperate to renderobject moveable with respect to the at least two additional cooperatingdegrees of freedom with respect to the two opposing pivot points oneither side of object 12. An example configuration of bearing arms 24 isillustrated in more detail in FIG. 2. Each of bearing arms 24 include afirst portion 26 and a second portion 28. “Each” refers to each memberof a set or each member of a subset of the set. First and secondportions 26 and 28 are rigidly fixed to one another. In the illustratedembodiment, a third portion 30 rigidly fixes first and second portions26 and 28 such that each bearing arm 24 resembles a skewed “z”. Theconfiguration of bearing arms 24, as illustrated in FIG. 2, however, ismerely one example embodiment of bearing arms 24. It is generallyrecognized that bearing arms 24 may be of an appropriate configurationfor movably coupling object to base 14. For example, in some embodimentsthird portion 30 may be unnecessary, and first and second portions 26and 28 may be rigidly fixed directly to one another in an appropriateangle for aligning object 12 at a desired position respective to base14.

As discussed above, bearing arms 24 couple object 12 to base 14.Accordingly, first portion 26 of each bearing arm 24 is coupled toobject 12 on opposing sides of object 12 at opposing pivot points. Firstportion 26 is coincident with a third axis 32. In particularembodiments, third axis 32 comprises an elevation axis, about whichobject 12 may be rotated. For example, the elevation axis may extendalong a plane that is substantially parallel to the page. Where object12 comprises a sensor package mounted on the turret of a vehicle, thirdaxis 32 may allow object 12 to be rotated 180 degrees relative to thehorizon. Third axis 32 represents a second degree of freedom thatcooperates with the first degree of freedom provided by second axis 22.Thus, first axis 20, or the line of sight or horizontal field, may bealigned with a target at any elevation respective to the vehicle orother machinery or structure supporting system 10.

Second portion 28 of each bearing arm 24 is coupled to base cradle 18.Second portion 28 is coincident with a fourth axis 34. Fourth axis 34 isskewed from third axis 32 by a deroll angle 36 and, therefore, comprisesa deroll axis. As a result, bearing arms 24 support object 12 in a firstposition along fourth axis 34 that is skewed by deroll angle 36 relativeto third axis 32. In particular embodiments, deroll angle 36 is skewedfrom third axis 32 by an amount within a range that is greater than zerodegrees but less than 90 degrees. Because first and second portions 26and 28 are coincident with third and fourth axes 32 and 34,respectively, and because bearing arms 24 couple to object 12 atopposing pivot points on opposing sides of object 12, object 12 ismovable with respect to both third axis 32 and fourth axis 34 fromcommon pivot points associated with object 12. In operation, bearingarms 24 may be used to adjust the position of object 12 from the firstposition to a second position when a tilt of base 14 is detected. Theadjustment or repositioning of object 12 may include rotating object 12about second axis 22 and third axis 32 in conjunction with fourth axis34 to establish or maintain first axis 20. Accordingly, fourth axis 34represents a third degree of freedom. Rotating object 12 about fourthaxis 34 may induce a tilt between first axis 20 and base 14 tocompensate for a vehicle induced tilt experienced by base 14 and, thus,object 12.

As discussed above, system 10 may include a director or controller thatoperates to control the position of object 12. The director orcontroller may adjust the position of object 12 from a first, unadjustedposition to a second, adjusted position by moving bearing arms 24. Theobjective of repositioning object 12 is to substantially maintain thealignment of object 12 with first axis 20. More specifically and asdescribed above with regard to FIG. 1, base 14 of system 10 may bemounted on a vehicle or other machine in a state of motion. A line ofsight or other horizontal field such as first axis 20 may be establishedby object 12 and object 12 may be positioned appropriately. As themachinery on which system 10 is mounted travels along a surface orthrough the air, the machinery may encounter obstacles or elevationchanges that cause the machinery to rise or fall relative to thehorizon. Such changes in the elevation of the machinery with respect tothe horizon, however, may alter the position of object 12 relative tothe established line of sight or other generally horizontal field.

However, for strategic purposes it may be desirable for object 12 tomaintain a substantially constant line of sight with the identifiedtarget. For example, it may be desirable for an object 12, whichcomprises a sensor package for producing image or thermal sensoryinformation for a target located some distance from object 12, tomaintain a substantially constant line of sight with the target oranother generally horizontal field. Because bearing arms 24 enableobject 12 to be rotated about both third axis 32 and fourth axis 34,bearing arms 24 may cooperate with base 14 to adjust object 12 to asecond position to maintain first axis 20 when a tilt angle of base 14is detected relative to the horizon or another fixed and substantiallyhorizontal reference. Because bearing arms 24 cooperate to adjust theposition of object 12 about third axis 32 and fourth axis 34 from commonpivot points on opposing sides of object 12, however, the movement ofobject 12 with respect to either third axis 32 or fourth axis 34 resultsin a cooperative movement of object 12 with respect to the othercooperating axis as well.

For the maintenance of first axis 20, the controller or directordiscussed above may reposition object 12 with respect to each of thefour axes. The movement of object 12 with respect to each axis isindependently controlled by the controller or director. As stated above,however, because bearing arms 24 cooperate with two opposing arms ofbase cradle 18 to couple object 12 to base 14, however, the controlleror director independently controls the position of object 12 withrespect to third axis 32 and fourth axis 34 through the same two contactpoints. The movement of object 12 with respect to either axis results ina movement of object 12 about the cooperating axis. For example,adjustment of the position of object 12 with respect to third axis 32results in the movement of object 12 with respect to fourth axis 34, andvice versa.

The amount of tilt for which bearing arms 24 may be able to compensatemay be directly related to, or a function of, the amount by which fourthaxis 34 is skewed from third axis 32. Thus, the amount of tilt for whichbearing arms 24 may compensate may be directly related to deroll angle36. As just one example, where object 12 is positioned such that fourthaxis 34 is skewed from elevation axis 32 by an amount on the order often degrees, bearing arms 24 may cooperate to maintain first axis 20when base 14 is tilted at any angle up to ten degrees. As anotherexample, where fourth axis 34 is skewed from elevation axis 32 by anamount on the order forty-five degrees, bearing arms 24 may cooperate tomaintain first axis 20 when base 14 is tilted at any angle up toforty-five degrees.

FIG. 3 illustrates a top view of one embodiment of object 12 with atleast three degrees of freedom. Object 12 is illustrated in a first,unadjusted position 50. Because FIG. 3 is a top view of object 12, firstaxis 20 is illustrated as being generally parallel to the page andsecond axis 22 is illustrated as being generally perpendicular to thepage. The position of object 12 relative to first axis 20 and secondaxis 22 is controlled by base 14. In first, unadjusted position 50,object 12 is positioned at a skewed angle relative to base cradle 18.The skew of object 12 is determined by deroll angle 36 and thus therelation of fourth axis 34 and third axis 32. While object 12 is infirst, unadjusted position 50, first axis 20, which may comprise a lineof sight or other generally horizontal field, is directed at anidentified target located some distance from object 12. Because secondaxis 22 allows for the rotation of object 12 in 360 degrees, theidentified target may be on any side of the machinery on which system 10is mounted. Because third axis 32 allows for the further rotation ofobject 12 about third axis 32, the identified target may also be at anyelevation relative to object 12 or relative to the combat vehicle onwhich object 12 is mounted.

Tilting of the vehicle or other machinery on which object 12 is mountedis related to the change in elevation of the machinery. As the machinerymoves, the machinery and, thus, base 14 on which object 12 is mountedmay be tilted such that base 14 is no longer substantially horizontal.As a result of the tilting, first axis 20 may be redirected away fromthe initial target. Accordingly, the line of sight with the target orother generally horizontal field may be broken. The director of system10 may detect the tilting of base 14 and operate to reestablish the lineof sight or generally horizontal field. In particular embodiments, thedirector of system 10 may receive global position satellite (GPS)information and determine the tilt angle of base 14 from the GPSinformation. Alternatively, system 10 may use a suitable orthogonalgrouping of gyroscopes, a system of pendulums, a tilt sensor, or othersuitable mechanism for establishing a fixed point of reference in spaceto determine the tilt angle of base 14. The position of object 12 maythen be adjusted to reestablish or generally maintain the line of sightor other generally horizontal field of object 12 with the initial targeteven when base 14 is tilted at the detected tilt angle. As discussedabove with regard to FIG. 2, the repositioning of object 12 may includeadjusting bearing arms 24 to cooperatively adjust the position of object12 relative to third axis 32 and fourth axis 34.

FIG. 4 illustrates a front view of one embodiment of object 12 with atleast three degrees of freedom in a second, adjusted position 60.Because object 12 is illustrated as a front view, first axis 20 nowextends in a direction that is generally perpendicular to the plane ofthe page. As described above, second, adjusted position 60 is obtainedby adjusting bearing arms 24 an amount required to compensate for a tiltrange of base 14 to substantially maintain a line of sight or othergenerally horizontal field with an identified target. Specifically,bearing arms 24 may be automatically and mechanically rotated aboutfourth axis relative to base 14. The rotation of bearing arms 24 aboutfourth axis 34 results in the rotation of third axis 32 about fourthaxis 34. In this manner, bearing arms 24 and base 14 may cooperate tocompensate for the tilt angle detected by the director of base 14 byadjusting bearing arms 24 relative to the pivot points at which bearingarms 24 couple object 12 to base 14.

The amount of tilt for which bearing arms 24 are able to compensate isrelated to deroll angle 36. Specifically, deroll angle 36 determines themaximum amount of tilt for which bearing arms 24 may be used to maintainfirst axis 20. As a first example, object 12 may be positioned such thatobject 12 is skewed relative to third axis 32 by a deroll angle 36 onthe order of ten degrees. Because the amount of tilt for which bearingarms 24 may compensate is determined by deroll angle 36, bearing arms 24are adjustable to compensate for a maximum of ten degrees of tilt inthis example. Accordingly, if base 14 experiences a tilt of ten degreesor less, bearing arms 24 may be used to reposition object 12 in second,adjusted position 60 to maintain first axis 20. If base 14 experiences atilt of more than ten degrees, however, object 12 may not berepositioned to maintain first axis 20. Rather, for a tilt angle that isgreater than deroll angle 36, the line of sight with the target or othergenerally horizontal field must be at least partially reestablishedmanually.

FIG. 5 illustrates another embodiment of a system 200 for adjusting theposition of an object 12. As illustrated, object 12 is supported on arotatable base 14 that may be mounted on the turret of a vehicle orother movable machine. In particular embodiments, base 14 includes abase support 16 and a base cradle 18. Base cradle 18 is rigidly fixed tobase support 16 and includes a single arm to couple object 12 to basesupport 16. Similar to system 10 of FIG. 1, base support 16 is rotatablerelative to the machinery on which base 14 is mounted. Because basecradle 18 is rigidly fixed to base support 16, however, the rotation ofbase support 16 relative to the vehicle or other supporting machinerycauses the rotation of base cradle 18 and, thus, object 12, which issupported thereon.

Because object 12 is coupled to base 14 at a single pivot points object12 is coupled to base 14 and, thus, mounted on any supporting machineryusing a collarless mounting system. As a collarless mounting system,system 200 may provide a smaller structure than other mass derolls. As aresult, system 200 is substantially lighter and stiffer than collaredmounting systems, and less mass must be moved to maintain first axis 20when base 14 encounters tilt. Additionally, because system 200 issupported by a single bearing arm 18, system 200 is substantiallylighter than system 10 with two bearing arms 18. As an additionaladvantage, the unobstructed sensor surface area that may be used forobtaining sensor data may be substantially increased.

Similar to system 10, system 200 includes a director or controller, notillustrated, that operates to control the position of object 12 and themovement of all axes. For example, the director may control the rotationof object 12 about first axis 20 defined by object 12. As illustrated,first axis 20 extends outward from object 12 in a direction that issubstantially perpendicular to the page. In particular embodiments,first axis 20 may include a line of sight or other generally horizontalfield defined by or established by or established by object 12. Theposition of object 12 may be controlled relative to this line of sightor horizontal field.

Base 14 also operates to control the position of object 12 about asecond axis 22. Object 12 may be stabilized with respect to second axis22. In particular embodiments, second axis 22 is an azimuth axis whichdefines 360 degrees of rotation. Base cradle 18 couples to base support16 to establish second axis 22 rotation with respect to the vehicle.Base cradle 18 may be rotated about second axis 22 to enable object 12to also rotate 360 degrees about second axis 22. Thus, where object 12comprises a sensor package mounted on the turret of a combat vehicle,the sensor package may be rotated 360 degrees relative to azimuth axis22. As a result, first axis 20, or the line of sight defined by object12, may be directed at and aligned with any target on any side of thecombat vehicle. The rotation of object 12 about second axis 22represents a first degree of freedom.

FIG. 6 is a flowchart of one embodiment of a method for adjusting theposition of object 12 according to the present invention. At step 100, arotatable base 14 is provided. As discussed above, base 14 may comprisea base support 16 and a base cradle 18 and may be supported on any of avariety of combat vehicles or machinery. For example, base 14 may besupported on a tank, an airplane, a ship, or other vessel or machine andmay be in a state of motion. In particular embodiments, base 14 couplesto object 12 using a collarless-mounting system that provides adjustmentof object 12 from two pivot points on opposing sides of object 12. Atstep 102, second axis 22, or an azimuth axis, and third axis 32, anelevation axis, are provided.

At step 104, an object 12 is supported on base 14 at deroll angle 36.Object 12 may be supported on base 14 by the two opposing arms of basecradle 18 that are each coupled to opposing sides of object 12,respectively. In the supported position on base 14, object 12 may bestabilized along second axis 22 and third axis 32. In particularembodiments, object 12 may also be stabilized along an azimuth axis thatprovides a first degree of freedom of 360 degrees.

At step 106, a line of sight is established. Where, for example, object12 comprises a sensor package operable to perform image sensory, thetarget may include a person, a military vehicle, or other appropriatetarget. Once a line of sight to a target is established, object 12 ispositioned at first position 50 at step 108. Object 12 may be positionedin first position 50 relative to base 14 by moving or repositioningbearing arms 24. The position of bearing arms 24 and, consequently,object 12 is controlled relative to first axis 20. In particularembodiments, first axis 20 may include a line of sight or othergenerally horizontal field that is directed at the identified target.Accordingly, positioning object 12 in first position 50 may includerotating object 12 about second axis 22, which may comprise an azimuthaxis in particular embodiments. Additionally, first position 50 mayinclude object 12 positioned relative to third axis 32 and fourth axis34, which may comprise, in particular embodiments, an elevation axis anda deroll axis, respectively.

At step 110, a tilting of base 14 is detected. As described above, thetilting of base 14 may result from a change in pitch, roll, or elevationof the machinery on which base 14 and, thus, object 12 is mounted. Forexample, if base 14 is mounted on a tank, the surface on which the tankis moving may be uneven and cause the line of sight or other generallyhorizontal field of object 12 to be moved from the identified target.Accordingly, in response to a detection of a tilting of base 14, theposition of object 12 may be adjusted to a second position to compensatefor the tilting of base 14 at step 112. Specifically, bearing arms 24may be rotated to adjust object 12 to second position 60 to maintainfirst axis 20 even when of base 14 is tilted. Accordingly, object 12 maybe rotated about third axis 32 and fourth axis 34, which cooperate toremove the tilt. Additionally, second axis 22 and third axis 32 may beadjusted to substantially maintain first axis 20. Thus, the line ofsight or other generally horizontal field of object 12 may be maintainedon the identified target even though base 14 and object 12 are in astate of motion.

Because object 12 is coupled to base 14 at two opposing pivot points onopposing sides of object 12, base 14 comprises a collarless mountingsystem, which provides a smaller structure than other mass derolls. As aresult, system 10 is substantially lighter and stiffer than collaredmounting systems, and less mass must be moved to maintain first axis 20when base 14 encounters tilt. Additionally, the unobstructed sensorsurface area that may be used for obtaining sensor data may besubstantially increased.

Although example steps are illustrated and described, the presentinvention contemplates two or more steps taking place substantiallysimultaneously or in a different order. In addition, the presentinvention contemplates using methods with additional steps, fewer steps,or different steps, so long as the steps remain appropriate foradjusting the position of an object to generally maintain a line ofsight or other generally horizontal field or axis.

Although an embodiment of the invention and its advantages are describedin detail, a person skilled in the art could make various alterations,additions, and omissions without departing from the spirit and scope ofthe present invention as defined by the appended claims.

1. A system for adjusting a position of a sensor package to compensatefor tilt, the system comprising: a sensor package having a firstposition controlled relative to a line of sight directed at a target,the sensor package stabilized along an azimuth axis; a base operable tosupport the sensor package; and a bearing arm movably coupling thesensor package to the base, the sensor package coupled to the base at afirst position relative to an elevation axis and a deroll axis, theelevation axis perpendicular to the line of sight, the base controllingrotation of the sensor package about the azimuth axis; wherein thebearing arm comprises a first portion and a second portion, the firstand second portions of the bearing arm rigidly fixed relative to oneanother, the first portion coupled to the sensor package and coincidentwith the elevation axis, the second portion coupled to the base andcoincident with the deroll axis, such that the bearing arm is operableto hold the sensor package at a deroll angle relative to the elevationaxis, the deroll angle greater than zero degrees but less than ninetydegrees, the bearing arm operable to adjust the sensor package to asecond position to maintain the line of sight when a tilt angle of thebase is detected.
 2. A system for adjusting a position of an object tocompensate for tilt, the system comprising: an object having a firstposition controlled relative to a first axis, the object stabilizedalong a second axis; a base operable to support the object; and abearing arm movably coupling the object to the base, the object coupledto the base at a first position relative to a third axis and a fourthaxis, the third axis perpendicular to the first axis, the basecontrolling rotation of the object about the second axis; wherein thebearing arm comprises a first portion and a second portion, the firstportion coupled to the object and coincident with the third axis, thesecond portion to the base and coincident with the fourth axis, suchthat the bearing arm is operable to hold the object at a deroll anglerelative to the third axis, the deroll angle greater than zero degreesbut less than ninety degrees, the bearing arm operable to adjust theobject to a second position to maintain the first axis when a tilt angleof the base is detected.
 3. The system of claim 2, wherein the objectcomprises a sensor package operable to be directed along the first axisat a target.
 4. The system of claim 3, wherein the sensor package isoperable to perform image sensory.
 5. The system of claim 2, wherein thefirst and second portions of the bearing arm are rigidly fixed relativeto one another.
 6. The system of claim 2, wherein: the first axiscomprises a line of sight perpendicular to a target positioned somedistance from the object; the second axis comprises an azimuth axisrepresenting a first degree of freedom; the third axis comprises anelevation axis representing a second degree of freedom; and the fourthaxis comprises a deroll axis representing a third degree of freedom. 7.The system of claim 2, wherein the tilt angle is a function of thederoll angle.
 8. The system of claim 2, wherein the base is coupled to avehicle.
 9. The system of claim 2, further comprising a directoroperable to adjust the bearing arm to adjust the object to the secondposition.
 10. The system of claim 9, wherein the director is furtheroperable to receive global position satellite information to identifythe tilt angle of the base.
 11. The system of claim 9, wherein thedirector is further operable to identify the tilt angle of the base frominformation received from a system of one or more tilt sensors.
 12. Asystem for adjusting a position of an object to compensate for tilt, thesystem comprising: an object having a first position controlled relativeto a first axis, the object stabilized along a second axis; a baseoperable to support the object; and a bearing arm movably coupling theobject to the base, the bearing arm coupled to the object at a pivotpoint, the object coupled to the base at a first position relative to athird axis and a fourth axis, the third axis perpendicular to the firstaxis, the base controlling rotation of the object about the second axis;wherein the bearing arm comprises a first portion and a second portion,the first portion coupled to the object and coincident with the thirdaxis, the second portion coupled to the base and coincident with thefourth axis, the bearing arm operable to adjust the object to a secondposition to maintain the first axis when a first tilt angle of the baseis detected.
 13. The system of claim 12, wherein the object comprises asensor package operable to be directed along the first axis at a target.14. The system of claim 13, wherein the sensor package is operable toperform image sensory.
 15. The system of claim 12, wherein the first andsecond portions of each bearing arm are rigidly fixed relative to oneanother.
 16. The system of claim 12, wherein: the first axis comprises aline of sight perpendicular to a target positioned some distance fromthe object; the second axis comprises an azimuth axis representing afirst degree of freedom; the third axis comprises an elevation axisrepresenting a second degree of freedom; and the fourth axis comprises aderoll axis representing a third degree of freedom.
 17. The system ofclaim 12, further comprising a director operable to adjust the first andsecond bearing arms to adjust the object to the second position.
 18. Thesystem of claim 17, wherein the director is further operable to receiveglobal position satellite information to identify the tilt angle of thebase.
 19. The system of claim 17, wherein the director is furtheroperable to identify the tilt angle of the base from informationreceived from a system of one or more tilt sensors.
 20. A system foradjusting a position of an object to compensate for tilt, the systemcomprising: an object having a first position controlled relative to afirst axis, the object stabilized along a second axis; a base operableto support the object; and at least one bearing arm movably coupling theobject to the base, the object coupled to the base at a first positionrelative to a third axis and a fourth axis, the third axis perpendicularto the first axis, the base controlling rotation of the object about thesecond axis; wherein the bearing arm is to adjust the object to a secondposition to maintain the first axis when a first tilt angle of the baseis detected.